1. Field of the Invention
The present invention relates to a support structure for a steam condensation system and installation of the support structure.
2. Description of the Related Art
Installations for condensing turbine or process exhaust steam have already been used for many years in very large dimensions in the energy technology sector (DE 199 37 800 A1). Air-cooled condensers serve for the direct condensation of turbine exhaust steam. They can be considered to be a special usage case of air-cooled heat exchangers. Air-cooled heat exchangers serve for cooling fluids by means of ambient air in various processes in the chemical, petrochemical and electricity generation industries. The heat exchangers are composed substantially of heat exchanger tubes which, owing to the poor thermal conductivity of the air, are provided with fins on the outer side in order to improve the heat transfer. The heat transfer to the cooling medium, air, by means of heat exchangers by heat conduction and convection is commonly also referred to as dry cooling. The heat exchanger tubes of air-cooled heat exchangers are combined to form so-called bundles by being welded into planar, perforated, thick-walled metal sheets, also referred to as tube plates. Said bundles are referred to as fin-tube bundles or tube bundles.
The inflow of the fluid to be cooled into the heat exchanger tubes is realized by means of steam distribution lines which are welded to the tube plates at the top. The outflow of the condensate and the distribution of excess steam is realized by means of condensate collectors which are welded to the tube plates at the bottom.
The cooling medium, air, is conveyed through the heat exchanger bundle by means of fans which are arranged so as to impart a suction or pressure action. A common type of construction is the so-called roof type of construction. In the case of this arrangement, fans are situated, in an arrangement for imparting a pressure action, below heat exchanger bundles arranged in roof-shaped fashion. The heat exchanger bundles arranged in roof-shaped fashion with the fans are borne by a support structure, wherein the fans are borne by a fan bridge.
The adaptation of air-cooled condensation installations to the quantity of exhaust steam or turbine size and to the operating and ambient conditions (air temperature) may basically be realized through variation of the heat exchanger surface area and/or through variation of the cooling air flow.
For the delivery of the cooling air, it is the case in all air-cooled heat exchangers for industrial applications that fans of axial type of construction are used, because these are suitable for delivering the required large volume flows with low pressure differences.
If multiple heat exchanger bundles are assigned to one or more fans such that the heat flow transferred by the heat exchanger bundles and the cooling air volume flow that absorbs said heat are in equilibrium, there is, depending on the type of construction, a basic geometric pattern which is also referred to as module. If the modules or cells are arranged in series (series connection), so-called multi-cell, single-row installations are realized. Owing to the supply of air from below, cells or modules of roof type of construction may also be produced through parallel connection of multiple roof rows of air-cooled condensers of virtually any desired size.
The major advantage of the roof type of construction consists in the possibility of producing even very large installations by way of the parallel and series connection of the individual cells. The fans arranged below the heat exchanger bundles must, however, in the case of the roof type of construction, be equipped with protective grilles for the purposes of protection against falling parts or damage to the fan. Furthermore, the fan ring, which is arranged around the fan for the purposes of realizing defined flow conditions, reduces the air inlet height. As a result, the support structure on which the heat exchanger bundles lie must be correspondingly elevated.
A further disadvantage may arise as a result of the recirculation of the heated cooling air. Owing to the low hot-air speeds in the case of the roof type of construction of the condensers, a so-called wind wall must be installed around the outer heat exchanger elements, which are composed of an additional support structure with wind wall panels.
Furthermore, in the case of the roof type of construction, it is necessary to provide encircling access means for permitting cleaning of the heat exchanger elements.
Heat exchanger bundles in a V-shaped arrangement with fans situated at the top can be erected with a small structural height, but in the case of heat exchanger bundles which are not self-supporting, very cumbersome support structures are required (DE 103 23 791 A1). Heat exchangers of V-shaped type of construction are therefore usually used only in the field of process coolers with horizontally arranged heat exchangers (water return coolers, air-conditioning technology). There, the structural sizes are significantly smaller, whereby the support structure for the V-shaped arrangement can be made economically. The fans are also correspondingly smaller and lighter. In the case of relatively large installations, the support structure is however always relatively cumbersome, and has hitherto proven to be uneconomical.
DE 10 2007 012 539 B4 discloses, in the case of fans situated at the bottom and heat exchanger elements arranged in roof-shaped fashion thereabove, the mounting of a frame-like fan panel on a reduced number of supports in order to reduce the outlay with regard to the steel structure. Below each fan panel, there is provided at least one support in the form of a column running vertically to the fan panels, wherein, above the column, there are adjoining head struts which run obliquely relative to the fan panel and the column and which extend to the corners of a fan panel. The fans themselves are mounted on or on top of the fan panels.
U.S. Pat. No. 8,235,363 B2 discloses as prior art a heat exchanger arrangement in which a cooling tower is assembled from heat exchanger bundles, in particular in a hexagonal arrangement. The fan is situated above the bundles. Several of these tower modules may be arranged adjacent to one another. The surfaces of adjacently arranged modules which are in contact however do not participate in the exchange of heat. The fan is mounted on a central pillar. At the upper end of the tower there is situated a bridge which is supported by means of end-side support pillars on the ground. The support structure thus takes the form of a bridge with three pillars. It is a disadvantage that, for each individual module, a relatively cumbersome steel structure and a highly complex steam distribution line are required. For each individual cell, three foundations for the three supports are required. Furthermore, a series and parallel connection of the individual modules for the purposes of erecting relatively large installations is not possible.